Yb3+-Er3+-Tm3+ co-doped nano-glass-ceramics tuneable up-conversion phosphor

Transparent Yb3+-Er3+-Tm3+ co-doped nano-glass-ceramics have been prepared, 32(SiO2) 9(AlO1.5) 31.5(CdF2) 18.5(PbF2) 5.5(ZnF2): 3.5(Yb-Er-TmF3) mol%, where the co-dopants partition mostly to the fluoride PbF2-based nano-crystals. A comparative study of the up-conversion luminescence in nano-glass-ceramics and its precursor glass indicates that these materials can be used as blue/green/red tuneable up-conversion phosphor, in particular for white light generation. A ratio between blue, green and red emission bands of the Tm3+ and Er3+ can be widely varied with nano-ceramming of the precursor glass and with changing a pump power of luminescence. The change in the ratio between the blue, green and red emission bands is explained to be due to substantial lowering phonon energy and shortening of inter-dopant distances with nano-ceramming of the precursor glass and due to change in the ratio of 2- and 3-photon up-conversion processes with pump power.